Diesel pilehammer



- April 8, 1969 5, BAlLEY ET AL DIESEL PILEHAMMEH Filed Dec. 2. 1966FIG.

2 8 53 7 m 44 l HM n in k i| M 4 Q o o 4 V 4 w 5 3 4 5 m 6 MM 4 L 1 w 53 7 3 m. 4 6 5 7 3 I L 2 i E- E II. w o i J o 4 V .I 9 6 .1 .J 6/ 2 n 3w M 5 l TIT, Z .6 4 3 Av o o o in i i I F E f 5; W 5: 3 I8 J .J 3 o 5 .H6 l}: 9 N H .6

INVENTORS KENNETH E. BAILEY LELAND J. FRAHM THEODORE M. LEIGH ATZY April8, 1969 K. E. BAILEY ET AL DIESEL PILEHAMMER Sheet Filed Dec. 2. 1966TORS INVEN KENNETH E. BAILEY LELAND J. FRAHM THEODORE M. LEIGH ATT April8, 1969 K. E. BAILEY ET AL DIESEL PILEHAMMER Filed Dec. 2. 1966 Sheet .5of8 IN VEN TORS KENNETH E. BAILEY LELAND J. FRAHM THEODORE M. LEIGH ATTYApril 8, 1969 K. E. BAILEY ETAL 3,437,157

DIESEL PILEHAMMER Filed Dec. 2,.1966 Sheet 4 INVENTORS KENNETH E. BAILEYLELAND J. FRAHM THEODORE M LEIGH ATT Y April 8, 1969 K. E. BAILEY ET AL3,437,157

DIESEL PILEHAMMER Filed Dec. 2. 1966 Sheet 5 of a F/GQ.

I INVENTORS O3 96 KENNETH E. BAILEY I02 08 LELAND J. FRAHM THEODORE M.LEIGH I07 /o4 /oo /o9 ATTY K. E. BAILEY ETAL April 8, 1969' DI ESEL PILEHAMMER Sheet Filed Dec.

INVENTO ETH E. BA LELAND J. FRAHM THEODORE M. LEIGH RS ILEY KENN ATTYApril 8, 1969 BMLEY ET AL DIES EL PILEHAMMER Sheet Filed Dec. 2, 1966BAILEY J. FRAHM ATT Y;

INVENTORS ETH E.

KENN

LELAND THEODORE M. LEIGH f) m n WW mm a 9 @E United States Patent3,437,157 DIESEL PILEHAMMER Kenneth E. Bailey, Marion, Iowa, Leland J.Frahm, Mendota, Ill., and Theodore M. Leigh, Cedar Rapids, Iowa,assignors to FMC Corporation, a corporation of Delaware Filed Dec. 2,1966, Ser. No. 598,663 Int. Cl. E21b 1/00; E21c 3/00; B25d 9/00 US. Cl.173133 22 Claims ABSTRACT OF THE DISCLOSURE A diesel pilehammercomprising a housing having a bore formed therein for receiving a freepiston in sealing engagement therewith and slidably disposed therein forreciprocating axial movement; portions of the piston being formed tocooperate with corresponding portions of the housing for defining ascavenging chamber and a power chamber interconnected by a conduitincluding a valve for allowing gases to pass only in one direction fromthe power chamber to the scavenging chamber. The housing is formed witha port having valve means to allow gases to pass in one direction fromthe scavenging chamber to the atmosphere as the piston moves in adirection to decrease the volume of the scavenging chamber. The housingis also formed with a port for allowing the passage of gases to and fromthe power chamber. The free piston and housing cooperate to define acombustion chamber within the power chamber when the free piston is in aposition providing a minimum volume in the power chamber. The dieselpilehammer further comprises appropriate fuel injection means fordelivering fuel to the combustion chamber to be ignited and liftingmeans for raising the piston to its starting position. The lifting meansincludes a member for engaging a downwardly facing surface formed on thepiston and a latch mechanism for automatically retaining the liftingmeans in its lowermost position to facilitate control of the entirehammer at all stages of the hammer operation. The diesel pilehammer, asdescribed above, is a preferred embodiment of one of several apparatusfor carrying out a method of operating a diesel pilehammer includingigniting a compressed fuelair mixture in a combustion chamber underlyingthe piston to cause the piston to ascend; evacuating a space separatefrom the combustion chamber during the ascent of the piston; permittinggases to flow to said evacuated space from the chamber underlying thepiston while also admitting air into the latter space for the scavengingthereof during the ascent of the piston; reversing the direction ofmovement of the piston due to a reversal of the imbalance of forcesacting thereon; forcing the gases in the previously evacuated space toflow to the atmosphere during the descent of the piston; confining andcompressing air in the combustion chamber during the descent of thepiston; and injecting fuel intothe compressed air to be ignited forinitiating a subsequent cycle.

This invention relates to new and useful improvements in dieselpilehammers and deals more particularly with the operation and startingthereof.

A diesel pilehammer is one application of a one cylinder unbalanced freepiston diesel engine, wherein the piston strikes an anvil slidable inthe bore and resting on a pile. The impact of the piston on the anvilprovides the principal impetus to drive the pile. The combustion of thefuel air mixture beneath the piston raises it to a position where itwill have suificient impetus to again descend driving the pile further,and simultaneously the combustion provides a driving force on the ram.

Difficulties have been encountered in the past in the use of this typehammer when driving piling into soft 3,437,157 Patented Apr. 8, 1969ground. On previous designs, once a hammer was started on a lowresistance pile it sometimes ceased to continue the cycle after one ormore strokes. The reason for this was that on low resistance piling, theforces of combustion acting to raise the ram were reduced by the rapiddrop of the anvil. Thus the length of ram stroke was reduced and theamount of fresh air drawn in by the scavenging system was reduced. Thereduced amount of oxygen trapped on the subsequent compression strokefurther reduced the forces of combustion resulting in still shorter ramstroke length and thus the hammer ceased to operate after a few strokes.

A further difficulty encountered with scavenging systems on someexisting diesel pilehammers is caused from their utilizing energy of thedescending ram for scavenging the power chamber. The principal drivingenergy is supplied by the energy of the descending piston, and anyutilization of this energy for other purposes subtracts from the drivingforce.

To start the diesel cycle the free piston is mechanically raised to astarting position and then released to compress the fuel-air mixture forignition. Existing designs of lifting mechanisms have required a slot inthe cylinder wall to provide access for the lifting lever to engage thepiston and/or have been a complex over-center toggle linkage which issubject to failure. The lifting mechanisms requiring the access slotalong the cylinder are mounted on or adjacent to the side of the hammer.Therefore, the lifting force is applied in a manner to cause anoff-center skewing force to the hammer. This imbalance of forces tendsto cock the hammer and cause the driving forces to be improperlyapplied.

It is the primary object of the invention to improve the operation of adiesel pilehammer on all types of piling, especially piling driven intosoil offering low resistance.

Another important object of the invention is to provide aself-scavenging system that will supply sufficient oxygen for combustionwhen the piston stroke is shortened due to low resistance piling.

Another object of the invention is to provide a scavenging system thatdoes not subtract energy from the descending piston that could beutilized for pile driving.

Still another object of the invention is to provide an integral scavengepump formed by the annular chamber between stepped diameter portions ofthe ram and cylinder.

A further object of the invention is to provide a reliable pistonlifting mechanism having few parts.

A still further object of the invention is to provide a liftingmechanism, having few parts, that will permit oncenter lifting of thepiston for starting.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

While, for the sake of clearness in illustration, the hammer is shownand described in use as a pilehammer with the cylinder in asubstantially upright position, but it is obvious that the hammer may bearranged to operate in a position inclined to the vertical as may berequired for various types of uses to which the hammer is applicable.

In the accompanying drawings, forming a part of this specification andin which like reference characters are employed to designate like partsthroughout:

FIGURE 1 and 1a is a side elevational view, partly in section, of adiesel pilehammer embodying the invention;

FIGURE 2 and 2a is a rear elevational view, partly broken away, of adiesel pilehammer embodying the invention;

FIGURE 3 and 3a is a front elevational view, partly broken away, of adiesel pilehammer of the present invention;

FIGURE 4 is a fragmentary view, partly elevational and partly sectional,showing the relative position of the scavenging ports and intake-exhaustports in the housings of the diesel pilehammer illustrated in FIGS. 1,1a, 2, 2w, 3 and 3a.

FIGURE 5 is a sectional view taken on line 55 of FIG. 4 showing thecross-section of the intake-exhaust ports;

FIGURE 6 is a sectional view taken on line 6-6 of FIG. 4, showing a planview of the scavenging ports;

FIGURE 7 is a sectional view taken on line 7-7 of FIG. 6;

FIGURE 8 is an enlarged fragmentary view of the lower portion of thelifting mechanism shown in FIG. 2a;

FIGURE 9 is a sectional view of the lifting mechanism illustrated inFIG. 8;

FIGURES 10, 11, 12, 13, 14, and are schematic representations of theoperating cycle of the diesel pilehammer employing the first embodimentof the present invention;

FIGURES 16, 17, 18, 19, and 21 are schematic representations of theoperating cycle of a diesel pilehammer employing the second embodimentof the present invention;

FIGURE 22 is a schematic representation of the third embodiment of thepresent invention;

FIGURE 23 is a thermodynamic digram showing the pressure-displacementrelationship of the power chamber of a diesel pilehammer embodying thepresent invention;

FIGURE 24 is a thermodynamic diagram showing the pressure-displacementrelationship of the scavenge chamber of a diesel pilehammer embodyingthe present invention;

FIGURE 25 is a thermodynamic diagram showing the pressure-displacementrelationship of the bounce chamber of a diesel pilehammer embodying thepresent invention.

In the drawings, wherein are shown the preferred embodiments of thisinvention, and first particularly referring to FIGS. 1, 1a, 2, 2a, 3,and 3a, there is shown a diesel pilehammer 27 having an upper cylinder28 and a lower cylinder 29 connected by bolting together mating flanges31 and 32. The bore 33 of the upper cylinder 28 is of a larger diameterthan the bore 35 of the lower cylinder 29. At the upper end of the uppercylinder 28, an upper cylinder head 34 is secured to the upper cylinder28 by bolting together mating flanges 36 and 38. This upper cylinderhead 34 contains a guide sheave assembly 37 to guide the starting andlifting rope from the off-center starting mechanism to an on-centerhoisting location.

The lower cylinder is closed at its lower end by the anvil 39 which isslidable in the lower portion of the bore of the lower cylinder 29. Theanvil 39 is retained by means of the anvil retainer 41 which is boltedto the bottom flange of the lower cylinder 29. The anvil 39 is equippedwith compression rings 42a to seal the lower end of the bore 35 of thelower cylinder 29.

Beneath the anvil 39 and guided by the anvil retainer 41 is a cushionadapter plug 43 which transmits the energy from the anvil 39 to thecushion 44 which fits over the lower end of the cushion adapter plug 43,and has a spherical lower surface 45 which mates with the sphericalupper surface of the driving head 42. The cushion adapter plug 43 has acentral outwardly extending flange 46 which projects a short distancebelow the bottom surface 47 of the anvil retainer 41. In the spacebetween the flange 46 and the bottom surface 47 of the anvil retainer 41an annular ring of elastomeric material 48 is located. The elastomericmaterial serves as a recoil dampener and absorbs the energy of recoilfrom a pile being driven. It also absorbs the shock if the hammer isdropped on the pile or if the hammer bounces on the pile duringoperation.

The anvil retainer 41 has a further function of providing a bearingsurface for the larger diameter portion 49 of the anvil 39 so thatsideward thrusts that would tend to cock the anvil are adequatelyresisted. Such side thrusts can be caused by pile misalignment,eccentricity and whip. The anvil retainer 41 also supports an alignmentpin 51 which enters a mating hole 52 in the enlarged diameter portion 49of the anvil 39. The purpose of this pin 51 is to prevent rotation ofthe anvil 39 during operation.

Within both the upper cylinder 28 and the lower cylinder 29 is the ram55, which is free to reciprocate vertically. The lower portion 56 of theram '55 is in sealing engagement with the bore 35 of the lower cylinder29 and defines a generally cylindrical power chamber 50 between thelower end of the ram and the anvil 39. The lower portion 56 contains awear ring 57 and compression rings 58 near its lower end to preventleakage of gases between the Wall of the cylinder bore 35 and the lowerportion of the ram 56. The wear ring has the function of acting as abearing ring to support the ram so that the cylinder bore 35 isprevented from coming in direct contact with the ram material. Near theupper end of the smaller diameter portion 56 of the ram 55 the diameteris varied to form a cam surface 59 to actuate a cam follower 60 thatdrives the fuel pump 61 and the lubrication pump 62. A short distanceabove the cam surface 59, the ram diameter is increased to form a largerdiameter portion 63. This larger diameter portion 63, which operatesonly in the bore 33 of the upper cylinder 28 has compression ring 64 atboth its upper and lower ends and a wear ring 65 therebetween. Thislarger diameter portion 63 of the ram 55 divides the upper cylinder intwo parts; a lower annular space which forms a scavenging chamber 53 anda cylindrical upper space which is a bounce chamber 54.

The housing is formed with outwardly extending ribs on which variousplates and accessories are attached to give the housing a substantiallyrectangular cross-section. FIGS. 1 and 1a illustrate one of two similarbut opposite handed sides of the diesel pilehammer 27. Illustrated inFIGS. 2 and 2a is the back of the hammer, and in FIGS. 3 and 3a is thefront of the hammer. For purposes of describing the exterior of thehammer the two sides of the hammer 27 will first be described as theyare illustrated in FIGS. 1 and la.

Formed as part of the upper cylinder are two guide angle pads 66 onwhich guides may be mounted to fit into corresponding leads to guide thetravel of the hammer in the direction that the pile is to be driven.Formed as part of the lower cylinder 29 are two radially outwardlyextending ribs 67. These ribs are also illustrated in FIG. 6. The ribs67 in cooperation with an outwardly extending flange 68, the flange 32,and a cover plate 69 bolted to the ribs form a scavenging passageway 70.The scavenging passageway 70 opens into the annular scavenging chamber53 through openings 76 in the flange 32. The rib 67 toward the frontside of the lower cylinder 29 is formed with openings 71 allowing gasesto pass to and from a space defined in the front portion of the housing,and to be described below.

Also illustrated in FIG. 1a is the combustion chamber 72 defined by asemi-spherical indentation 73 in the ram 55 and a correspondingsemi-spherical indentation 74 in the anvil 39. Opening from thesemi-spherical indentation 74 in the anvil 39 is a cylindricalpassageway 75. Mounted in the lower cylinder 29 is an injection nozzle78 which injects fuel for combustion through the passageway 75 into thecombustion chamber when the ram 55 nears its downward most position.

Formed in each side of the lower cylinder 29 are three intake-exhaustports 77. Referring now to FIG. 5 wherein is shown a cross-sectionalview of these ports, the intakeexhaust ports 77 open from the powerchamber 50 to the atmosphere to allow the exhaust gases to blow-downinto the atmosphere and to allow air to flow into the power chamber forscavenging. The ports 77 are shaped to direct the incoming air down intothe cylinder toward the anvil to sweep burned gases out of the powerchamber 50 and combustion chamber 72 during scavenging. Theintake-exhaust ports 77 are located so as to be the first ports in thelower cylinder to open as the ram rises during the power stroke.

Referring now specifically to FIGS. 2 and 2a, wherein is illustrated theback view of the diesel pilehammer 27, reference character 78 refers tocovers for the intake-exhaust ports which prevent foreign material fromentering the power chamber when the hammer 27 is not in operation.Toward the top end of the upper cylinder 2.8 are shown a series of fourports 81 which open from the bounce chamber 54, in the upper cylinder28, into an auxiliary bounce chamber 86 defined by the exterior of thehousing and a box shaped cover plate 85. The above mentioned auxiliarybounce chamber 86 serves as an overflow for air compressed in the bouncechamber 54 in the upper cylinder head 28 during the rise of the ram. Ifthe ram moves past its normal upward most position, it closes off theports 81 and enters a confined safety space in which the gases arerapidly compressed increasing the pressure in the confined safety spaceand retarding the upward movement of the ram to prevent the ram fromstriking the cylinder head 34.

Located on the lower cylinder 29 on the back side is the ram liftingmechanism 30 which is further illustrated in FIGS. 8 and 9. The ramlifting mechanism 30 includes a guide block 91 slidable vertically inways 92. Attached to and extending upward from the guide block 91 is apush rod 93 which passes through an opening 89 in flange 32 and engagesthe annular under surface 90 of the larger diameter portion 63 of theram 55. The push rod is guided through the upper flange 32 of lowercylinder 29 by means of a guide bushing 94 which also serves as a sealto prevent air leakage into the annular scavenging chamber 53. The guideblock 91 also serves as the attachment point of the hoist rope 95 usedto position and start the hammer.

The guide block 91 contains a latch mechanism used to lock the startingmechanism 30 in the downward position when using the hoist rope 95 tolift and position the hammer 27. Located in the guide block 91 is aspring loaded pin 96 which engages a latch block 97 bolted to the lowercylinder 29. Pivoted on the latch block 97 is a spring biased push arm98 which engages the spring loaded pin 96. Normally the pin is in itsoutward position to engage the latch block 97 and hold the liftingmechanism 30 in its downward most position so that the entire pilehammer27 may be hoisted and positioned by means of the 'hoist rope 95. Upontensioning of the latch release rope 99, the arm 98 slides the pin 96into the guide block 91 to allow the hoist rope 95 to raise the push rodlifting mechanism 30 to engage and lift the ram 55 to its properstarting position. The tension on the hoist rope 95 is then releasedallowing the ram 55 and push rod lifting mechanism 30 to descendcompressing fuel and air in the combustion chamber 72 for ignition. Thepush rod lifting mechanism 30 has its downward descent stopped by arecoil dampener 100 located on the lower cylinder housing 29 directlybeneath the guide block 91. The recoil dampener 100 includes a cupshaped housing 101 containing a sleeve 102 having a series of openings106 through its lower position. The sleeve 102 has a stepped bore toretain the pin 103, biased upward by the spring 104, within the bore ofthe sleeve 102. Hydraulic fluid is contained within the cup 101 andsleeve 102 upon downward movement of the pin 103, due to the descent ofthe guide block 91, the hydraulic fluid is compressed and forced throughthe openings 106 in the sleeve 102 and into the annular space 107defined between the outer wall 108 of the sleeve and the inner wall 109of the housing 101. The resistance of the hydraulic fluid to flowthrough the openings 106 causes the lifting mechanism 58 to come to asmooth halt allowing time for the spring loaded pin 96 to engage thelatch block 97.

The hoist rope 95 extends from the sheave guide mechanism 37 through atube 111 passing through the auxiliary bounce chamber 86. The tube 111is welded and sealed at both of its ends 112 so that the auxiliarybounce chamber 86 is hermetically sealed.

The hoist rope guide mechanism 37 includes a housing 110 having a flaredopening 114 at its upper portion through which the hoist rope entersfrom an independent lifting means (not shown). Also formed in thehousing is a radial slot 115 which opens into the flared opening andextends the entire length of the housing. Passing through the housingsubstantially perpendicular to and intersecting the slot 115 are twopins 116 which are fitted into appropriate holes 113 in the housing 110.One hole 113 is located below and in back of the other hole. Pivotallymounted on the pins 116 are two sheaves 117 and 118 located within theslot 115. Referring again specifically to FIG. 1 wherein is shown a sidecross-sectional view of the hoist rope guide means 37, the first sheave117 is located so that the hoist rope enters axially of the dieselpilehammer 27 and passes under the sheave 117. The second sheave 118 islocated below and in back of the first mentioned sheave 117 so that therope passes from the first sheave 117 and over the second sheave 118 andextends down the side of the housing through the tube 111. The purposeof the guide means 37 is to cause the hoisting force to be exerted on aline axially with the center of the housing to prevent any off-centerforce from cocking the angle of the pile hammer 27 while it is liftedand positioned on a pile to be driven. The flared opening 114 on thehousing 110 causes the hoist rope to enter the guide sheaves 117 and 118properly regardless of the amount of off lead present.

Referring now specifically to FIG. 3, wherein is shown the front view ofthe diesel pilehammer 27, reference character 119 refers to equalizingports positioned to be open when the ram is at its upward most positionallowing passage of air to the annular scavenging chamber 53 from theatmosphere to relieve any vacuum. The equalizing ports 119 are also openWhen the ram is in its lower most position allowing air to flow from theatmosphere into the cylindrical bounce chamber 54 to replace air losttherefrom through the compression rings during compression of the gasesin the bounce chamber 54. While the hammer is not in operation theequalizing ports 119 are sealed by the cover 120. Referring nowspecifically to FIGS. 1, la, 3, 4, 6, and 7 for a description of the sixscavenging ports denoted by reference character 122. The scavengingports 122 are located to open subsequent to the opening of theintake-exhaust ports 77 as the ram rises during the power stroke. Thesix scavenging ports 122 open into a chamber 123 defined by two radiallyextending ribs 67 and two outwardly extending flanges 124 and a coverplate 125 bolted to the ribs. The lower cylinder 28 is formed with sixrectangular lateral openings 131 and six three-sided deflector plateprojecting outward from the openings to form the scavenging ports sothat the gases are directed up through the chamber 123 during thescavenging cycle.

During the power stroke the ram rises to create a vacuum in thescavenging chamber 53 which draws air through the power chamber 50 tofacilitate the scavenging thereof. During scavenging the gases pass fromthe atmosphere through the intake-exhaust ports 77 and into the powerchamber 50 in a swirling fashion. Thence the gases flow from the powerchamber 50 through the scavenging ports 122 into the chamber 123. Theflow continues through the openings 71 in the nb 67 into the scavengingpassageways 70 on either side of the pilehammer 27. The gases then enterthe annular scavenging space 53 through the openings 76 in the flange32. As the ram descends it closes the scavenging ports 122 andcompresses the gases in the annular scavenging chamber 53 forcing thegases through the passageway into the chamber 123 and then out thescavenging valve 126. The scavenging valve 126 includes four openings121 in the plate 125 covered by two thin tempered metal plates 127,bolted along one edge to plate 125, which act as reed valves to allowpassage of gases only from the chamber 123 when the pressure therein israised a predetermined amount above atmospheric pressure. There are twosets of three scavenging ports 122, one set located on each of the twosides of the front portion of the diesel pilehammer 27. The arrangementof the scavenging ports 122 in relationship to the intake-exhaust ports77 is illustrated in FIG. 4.

Also attached to the front side of the diesel pilehammer 27 is the fueltank 128 with the lubrication tank 133 located therein. Directly beneaththe fuel and lubrication tanks is a protector 129 to guard the fuel andlubrication tanks 128 and 133 and the associated hoses and fittings.Located on the lower cylinder 29 is the lubrication pump 62 which isactuated by a cam follower 60 which engages the cam surface 59 on theram. On each stroke of the ram a predetermined amount of lubrication isdispersed to selected points within the bore of the two cylinders 28 and29. Also actuated by the cam follower 60 is the fuel pump mechanism 61which is of a standard type, as illustrated in American Bosch catalognumber APF-lCC 18OT-3035C. The fuel pump delivers a controllable amountof fuel to the nozzle 78 which injects said fuel into the sphericalcombustion chamber 72. The amount of fuel dispersed is controlledremotely by the controller 130 located generally a distance away fromthe diesel pilehammer. Also attached to the front side of the dieselpilehammer is a starting fluid injector which is described in Patent No.3,161,184 which only on the starting stroke may inject a predeterminedamount of starting fluid into the combustion chamber.

Method of operation FIGS. 10, ll, 12, 13, 14, and 15 illustrate thecycle of operation of a diesel pilehammer 27 as illustrated in FIGS. 1through 9 and show the position the ram and the condition of the variousports and valves during the cycle. For purposes of illustration, FIGS.10 through employ a solid arrow to show the movement of exhaust gases, apartially shaded arrow to show the movement of a mixture of exhaustgases and fresh air, and an open arrow to show the movement of freshair.

Referring now specifically to FIG. 10, ram 55 is at the bottom of itsstroke and impacting anvil 39 to start driving pile 151. Scavenging port122 and intake-exhaust ports 77 are closed, and air confined in thecombustion chamber 72 is compressed. Equalizing ports 119 are open toallow any air lost through the compression rings during the compressionof air in the bounce chamber to be replaced, to bring bounce chamberpressure up to atmospheric pressure. Nozzle 78 has injected fuel intocombustion chamber 72 and, ignition of the fuel air mixture is takingplace, raising the pressure between ram 55 and anvil 39 to start the rammoving upward and maintaining a driving force on pile 151.

FIG. 11 illustrates the condition of the hammer subsequent to thecombustion of the fuel air mixture in combustion chamber 72. Ram 55 hasrisen a sufiicient amount to close equalizing ports 119. Cam follower 60has descended down cam surface 59 on ram 55 allowing fuel injection pump61 to recharge. The upward movement of the ram creates a sub-atmosphericpressure in annular scavenging chamber 53 and compresses the confinedair in bounce chamber 54 and auxiliary bounce chamber 86. Thecompression of the confined air in the bounce chambers 54 and 86transfers some of the kinetic energy of the ram 55 into potential energyof the compressed air. Ram 55 in the position shown in FIG. 11 is stillsealing scavenging ports 122 but has allowed intake-exhaust ports 77 toopen, permitting burned gases in power chamber 50 to blow-down toatmospheric pressure.

FIG. 12 shows ram 55 after it has moved further upward, openingscavenging ports 122. Since scavenging chamber 53 and the scavengingpassageway 70, prior to the opening of scavenging ports 122, were at asub-atmospheric pressure, air at atmospheric pressure flows in throughintake-exhaust ports 77 scavenging power chamber 50 and combustionchamber 72 of burned gases. The

burned gas, scavenging air mixture is drawn through scavenging ports 122and into passageway 70 and scaveng ing chamber 53. As ram 55 continuesupward movement, it increases the volume of annular scavenging chamber53 drawing additional fresh air from the atmosphere through powerchamber 50 and into scavenging chamber 53. This process continues untilequalizing ports 119 are opened into scavenging chamber 53 to establishatmospheric pressure therein. The opening of equalizing ports 119 intothe scavenging chamber 53 is not essential to the operation and shouldnot occur until ram 55 has moved upward a sufficient distance to providefor adequate scavenging. Upward movement of ram 55 into bounce chamber54 compresses the confined air therein imparting additional energy fromthe ram to compress air.

Referring now specifically to FIG. 13, the ram 55 is illustrated in itsupward most position. As ram 55 has been moving upward, energy impartedto it by the forces of combustion undergoes conversion to potentialenergy of the ram, energy imparted to the air compressed in bouncechamber 54 and auxiliary bounce chamber 86, and work performed inreducing pressure in scavenging chamber 53 plus small amounts of workovercoming friction of the ram and windage of air and gases moved atatmospheric pressure. When all the kinetic energy of the ram 55 has thusbeen converted, the ram ceases its upward movement and begins itsdownward stroke.

FIG. 14 shows ram 55 after it has been acted upon by gravity and thepressure of the air in bounce chamber 54 which begins the descent of theram. The now highly dilute burned gases in scavenging chamber 53 andpassageway 70 are driven out scavenging ports 122, across power chamber50 and out intake-exhaust ports 77. Excess air beneath ram 55 and aboveintake-exhaust ports 77 also is blown out ports 77. Air in bouncechamber 54 expands to transfer the potential energy stored therein backto ram 55 as kinetic energy.

Referring now particularly to FIG. 15, wherein is shown ram 55 justprior to injection of fuel and combustion. As ramv 55 descends to thepoint shown in FIG. 15 it closes scavenging ports 122 and decreases thevolume of scavenging chamber 53 raising the pressure therein. When thepressure in scavenging chamber 53 and scavenging passageway 70 rises asuflicient amount above atmospheric pressure, scavenging valve 126 opensto vent the gases drawn into the scavenging chamber during thescavenging cycle. Upon closure of intake-exhaust port 77 by ram 55, airconfined in power chamber 50 is compressed between ram 55 and anvil 39.As ram 55 approaches anvil 39 cam follower 60 rides up cam surface 59,causing fuel pump 61 to begin delivery of fuel to injector 78. Bouncechamber air continues to expand imparting kinetic energy to ram 55 untilequalizing ports 119 open. When ram 55 strikes anvil 39, fuel injectionis complete and ignition begins. Impact of ram 55 on anvil 39 deliversthe rams energy to anvil 39 and thence to pile 151 through cushion block44 and driving head 42. After impact, ram 55 rises under action of theexpansion of the burning fuel-air mixture, and this expansion, acting onthe now descending anvil 39 transfers additional energy to the pile 151.

FIGS. 16, l7, 18, 19, 20, and 21 illustrate the cycle of operation of adiesel pilehammer 27 including the second embodiment of the invention.As described above the second embodiment of the invention issubstantially the same as the first embodiment with the inclusion ofreed valve 141 to allow flow of gases only from power chamber 50 topassageway 70, and not in the reverse direction. Since the operation ofequalizing ports 119, scavenging ports 122, scavenging valves 126, andintake-exhaust ports 77, are the same as in the description of themethod of operation of the first embodiment of the invention, they willnot again be described. The shading of the arrows shown in the figuresillustrating the cycle of operation of the second embodiment of theinvention have the same significance as in the description of the firstembodiment operation.

Referring now specifically to FIG. 16, wherein ram 55 is shown at thebottom of its stroke. Reed valves 141 are closed preventing the flow ofgases through scavenging ports 122. The slight positive pressure inscavenging passageway 70 holds the valves 141 closed.

Ram 55, as illustrated in FIG. 17, subsequent to ignition has risen aslight amount but yet still seals scavenging ports 122. Since scavengingports 122 have not yet opened, reed valve 141 still is in its closedposition.

After ram 55 has risen a suflicient amount to open scavenging ports 122,as illustrated in FIG. 18, the subatmospheric pressure in scavengingchamber 53 and passageway 70 causes reed valves 141 to move to theiropen position and remain there until the pressure in the passageway 70becomes atmospheric. FIG. 19 shows the ram at a position openingequalizing port 119 into scavenging chamber 53 raising the pressuretherein to atmospheric allowing reed valve 141 to close.

FIGS. 20 and 21 show ram 55 during its descent creating a slightpositive pressure in scavenging chamber 53 and passageway 70 closing 01freed valves 141 and preventing the flow of the dilute burned gases backinto power chamber 50. Excess air beneath ram 55 and aboveintake-exhaust ports 77 is blown out ports 77. The ram confines airwithin power chamber 50 and compresses said confined air prior toinjection of fuel and the combustion of the fuel air mixture to beginthe next cycle.

FIG. 22 is a schematic representation of the third embodiment of theinvention and corresponds to FIG. and FIG. 16, respectively, of thefirst embodiment and second embodiment of the invention. In the otherembodiments of the invention the equalizing port 119 opened to theatmosphere, as ram 55 approached the bottom of its stroke, in order tomake up the air lost during compression of air in bounce chamber 54. Inthe third embodiment of the invention bounce chamber 54 is connected byconduits 143 to the scavenging passageways 70. As ram 55 descends aslight positive pressure is created in scavenging chamber 53 andscavenging passageway 70. This embodiment of the invention allows theram as it approaches the bottom of its stroke to open port 145connecting the slight positive pressure in scavenging passageway 70, bymeans of the conduit 143, to bounce chamber 54 to make up any air lostfrom the bounce chamber during compression of the gases therein on theupstroke. Since the port 145 is connected to scavenging passageway 70'the negative pressure created during scavenging is not vented to theatmosphere, and the effective scavenging cycle is increased.

The operation subsequent to combustion of a pilehammer including thethird embodiment is the same as is illustrated in FIGS. 11, 12, 13, 14,and and described above.

Thermodynamic cycle FIGS. 23, 24, and show the pressure-displacementdiagrams for the first embodiment of this invention. For purposes ofpresentation diagrams of power chamber 50, scavenging chamber 53, andbounce chamber 54 are each shown separately. Vertical scales have beendistorted so that ordinate values of pressure are not to scale and donot depict true relative values. This is done for clarity, sinceatmospheric pressure (14.7 p.s.i.a.) would otherwise not be apparentwhen compared to peak compression pressure (500 to 600 p.s.i.a.) andpeak combustion pressure (1,000 to 1,200 p.s.i.a.).Pressure-displacement diagrams are used instead of pressure-volumediagrams so that the port and stroke relationship can be properlyrelated between the different curves.

Referring now specifically to FIG. 23, wherein is shown the cycle ofpower chamber 50. Starting at point 161 at the extreme left end of thecurve, which represents the top of the stroke, the pressure below ram 55in power chamber is atmospheric pressure. As ram descends (moving towardright along curve), the pressure remains atmospheric untilintake-exhaust ports 77 are closed (represented by point 162). Afterintake-exhaust ports 77 are closed the pressure beneath ram 55 risesapproxi mately adiabatically reaching peak compression pressure atbottom of stroke (represented by point 163). Assuming constant volumecombustion, the pressure rises vertically to peak combustion pressureindicated by point 164. Actually both anvil 39 and ram 55 move duringthe combustion pressure rise, but for simplicity a constant volumepressure rise is assumed. Upward movement of ram 55 (moving toward theleft along the graph) causes pressure to drop'approximatelyadiabatically to point 165 corresponding to the opening ofintake-exhaust ports 77. At this point blow-down of burned gases dropsthe pressure in power chamber 50 to atmospheric where it remains for therest of the cycle.

Referring now specifically to FIG. 24, wherein is shown thethermodynamic cycle of scavenging chamber 53. Starting at the extremeleft end of the curve (top of the stroke indicated by point 167), thepressure below the enlarged diameter of ram 55 in annular scavengingchamber 53 is atmospheric since equalizing ports 119, scavenging ports122, and intake-exhaust ports 77 are open to the atmosphere. As ram 55descends pressure in scavenging chamber 53 remains approximatelyatmospheric until the bottom of the stroke (indicated by point 168).When scavenging ports 122 are closed, there is a slight rise in pressurewhich is required to open scavenging valve 126. This pressure increasehowever is nominal and is here considered negligible. Upward movement ofthe ram (toward the left on the graph) now causes approximate adiabaticreduction of pressure below atmospheric. When the scavenging ports 122open (represented by point 169), gases from the power chamber 50 and airfrom the now opened intake-exhaust ports 77 raise the pressure quicklyto atmospheric where it remains for the rest of the cycle. The closingof the equalizing port 119 on the down stroke and its opening on the upstroke has no influence on the pressure-displacement relationship. Port119 only serves to provide some incidental aeration of scavengingcyclinder 53 which actually is a nonessential function.

FIG. 25 illustrates the thermodynamic cycle of the compression of air inbounce chamber 54 and its associated auxiliary bounce chamber 86. Thedescription of this curve will start at point 171 (at the extreme rightend of the diagram, bottom of the stroke) and proceed first to the left.The pressure in bounce chamber 54 and auxiliary bounce chamber 86 isatmospheric at point 171, since equalizing ports 119 are open from thebounce chamber to the atmosphere. The pressure remains atmosphericduring the short rise of the ram until equalizing ports 119 are closedby ram 55. Continued rise of ram 55 causes an approximate adiabaticpressure increase to the normal top of the stroke (indicated by point173). Descent of ram 55 results in an approximate adiabatic reduction inpressure which is shown by proceeding along the same curve as the riseof pressure to point 172. At point 172 equalizing ports 119 open intobounce chamber 54 to vent the same at which time the pressure becomesatmospheric and remains so until the equalizing ports are closed.

The thermodynamic cycle of power chamber 50, scav enging chamber 53,bounce chamber 54 and auxiliary bounce chamber 86 of the second andthird embodiments of the invention are substantially the same as thethermodynamic cycle described above.

It is to be understood that the forms of this invention herewith shownand described are to be taken as a preferred example of the same, andthat various changes in the shape, size, number, and arrangement ofparts may be resorted to without departing from the spirit of theinvention or the scope of the subjoined claims.

Having thus described the invention, we claim:

1. In a diesel pilehammer the combination of:

a housing having a bore,

a reciprocating free piston in sealing engagement with and slidablydisposed in the bore for axial movement therein, portions of the pistoncooperating with the housing to define a scavenging chamber and a powerchamber each having at least one movable wall,

valve means to allow gases to pass in one direction from the scavengingchamber tothe atmosphere when a movable wall of the scavenging chambermoves in a direction to decrease the volume thereof,

a conduit connecting the power chamber and the scavenging chamber toallow gases to pass from the power chamber to the scavenging chamberupon movement of a movable wall of the scavenging chamber in a directionto increase the volume thereof,

the housing having a port to allow passage of gases to and from thepower chamber,

the portions of the piston and housing defining the power chamber havingopposed surfaces spaced from each other to form a combustion chamberwhen a movable wall of the power chamber is in a position providing aminimum volume in the power chamber,

fuel injection means to deliver fuel to the combustion chamber forignition, and

lifting means to raise the piston to its starting position.

2. A diesel pilehammer as defined in claim 1 further characterized by:

means sealing one end of the bore and cooperating with the housing andpiston to form a bounce chamber having at least one movable wall movingin a direction to decrease the volume of the bounce chamber as a movablewall of the power chamber moves in a direction to increase the volume ofthe power chamber.

3. A diesel pilehammer as defined in claim 2 further characterized by:

a laterally disposed chamber; and

conduit means connecting the laterally disposed chamber to the bouncechamber.

4. A diesel pilehammer as defined in claim 3 further characterized by:

the conduit means being located in a position to be shut off by themovement of the piston in a direction to decrease the volume of thebounce chamber to create a cushion of gases between the sealing meansand the piston for arresting the movement thereof.

5. A diesel pilehammer as defined in claim 1 further characterized bythe housing including:

an anvil sealingly retained for limited axial movement in one endportion of the bore, portions of the anvil and piston having surfacesdefining walls of the combustion chamber.

6. A diesel pilehammer as defined in claim 2 further characterized by:

the housing having a port to equalize the pressure of the bounce chamberwith atmospheric pressure when the movable wall of the bounce chamber isat the position to provide for maximum volume in the bounce chamber.

7. A diesel pilehammer as defined in claim 6 further characterized by:

the equalizing port opening into the scavenging chamber to equalize thepressure therein with atmospheric pressure when the movable wall of thescavenging chamber is at the position to provide for the maximum volumein the scavenging chamber.

8. A diesel pilehammer as defined in claim 2 further characterized by:

the housing having a stepped cylindrical bore providing two coaxialportions, one portion having a diameter larger than the other forming ashoulder therebetween;

the piston having a portion in sealing engagement with each of the twoportions of the housing and a shoulder therebetween, the sealing meansin cooperation with the larger diameter portions of the housing andpiston defining the bounce chamber, the shoulders of the housing and thepiston cooperating to define the scavenging chamber, the smallerdiameter portions of the piston and housing defining the power chamber.

9. A diesel pilehammer as defined in claim 1 further characterized by:

valve means associated with the conduit to only allow flow of gases fromthe power chamber to the scavenging chamber.

10. A diesel pilehammer as defined in claim 2 further characterized by:

a conduit connecting the bounce chamber to the scavenging chamber toequalize the pressure therebetween when the movable wall of the bouncechamber is at a position providing maximum volume in the bounce chamber.

11. A diesel pilehammer including a housing, a reciprocating freepiston, and means for lifting the piston wherein the lifting meanscomprises:

a radially outwardly projecting portion on the piston;

a lifting mechanism including a rod slidably mounted on the housing formovement parallel to the reciprocation of the piston, the rod underlyingand engaging the radially outwardly projecting portion of the piston toimpart the lifting force thereto;

means associated with the lifting mechanism for applying a lifting forcethereto to raise the piston and for releasing the lifting mechanism toallow the mechanism to descend to its original position and to permitthe piston to descend to start the diesel cycle;

a cable interconnecting the rod and the force applying means;

means for fastening the cable to the rod; and

guide means associated with the housing to direct the path of movementof the cable.

12. A diesel pilehammer as defined in claim 11 wherein the guide meanscomprises:

a sheave mounted on the upper portion of the housing so that the cableengages the sheave substantially axially of the housing and passes underthe sheave;

a second sheave mounted on the upper portion of the housing and engagingthe cable to guide the cable into a path extending down the side of thehousing to the fastening means.

45 13. A diesel pilehammer as defined in claim 11 wherein the liftingmechanism further comprises:

a latching means operatively connected to the rod;

an abutment formed on the housing for cooperation with the latchingmeans to normally secure the rod in its down position and to cause anupward force applied by the cable to the lifting means to position theentire pilehammer.

14. A diesel pilehammer as defined in claim 11 wherein the lifting meansfurther comprises:

a cushioning means to stop the descent of the lifting rod after thelifting mechanism is released and to prevent the rod from rebounding toa position that would interfere with the descent of the piston.

15. The method of operating a diesel pilehammer including areciprocating free piston comprising:

igniting a compressed fuel-air mixture in a confined space underlyingthe piston to cause the piston to rise;

evacuating a space, separate from the space underlying the piston,during the rise of the piston;

permitting gases to flow to the evacuated space from the spaceunderlying the piston and admitting air into the latter space for thescavenging thereof during the rise of the piston;

reversing the direction of movement of the piston due to a reversal ofthe imbalance of the forces acting thereon;

forcing the gases in the previously evacuated space to flow to theatmosphere during the descent of the piston;

confining and compressing air in the space underlying the piston duringthe descent of the piston; and

injecting fuel into the compressed air prior to igniting the mixture.

16. The method of operating a diesel pilehammer including areciprocating free piston as defined in claim 15 further comprising:

confining and compressing gases in a space during the rise of the pistonto assist the reversal of the imbalance of force and to shorten thedistance the piston rises for increasing the cyclic rate.

17. The method of operating a diesel pilehammer including areciprocating free piston as defined in claim 15 further comprising:

preventing gases from flowing to the space underlying the piston fromthe evacuated space during the descent of the piston to prevent thereturn of scavenged gases to the space underlying the piston.

18. The method of operating a diesel pilehammer including areciprocating free piston as defined in claim 16 further comprising:

permitting air to flow into the last mentioned space when the pistonapproaches its downward most position to replenish any escaped gases.

19. The method of operating a diesel pilehammer including areciprocating free piston as defined in claim 16 further comprising:

permitting fluid communication between the last mentioned space and theevacuated space when the piston approaches its downward most position toequalize the pressure therebetween.

20. A diesel pilehammer including a housing, a reciprocating freepiston, and means for lifting the piston wherein the lifting meanscomprises:

a downwardly facing surface formed on the piston;

a lifting mechanism mounted on the housing and movable in a directionparallel to the reciprocation of the piston, the lifting mechanismhaving a portion for engaging the downwardly facing surface to raise thepiston to its starting position;

means associated with the lifting mechanism for applying a lifting forcethereto to raise the piston and for releasing the lifting mechanism toallow the mechanism to descend to its original position and to permitthe piston to descend for starting the diesel cycle;

a cable interconnecting the lifting mechanism and the force applyingmeans;

means for fastening the cable to the lifting mechanism;

means associated with the lifting mechanism and cooperating with aportion of the housing for automatically, releasably latching thelifting mechanism in its normal lowermost position to cause an upwardforce applied through the cable to the lifting mechanismto be imparteddirectly to the housing for positioning of the entire pilehammer; and

guide means associated with the housing to direct the path of movementof the cable.

21. A diesel pilehammer as defined in claim 20 wherein the guide meanscomprises:

a sheave mounted on the upper portion of the housing so that the cableengages the sheave substantially axially of the housing and passes underthe sheave; and

a second sheave mounted on the upper portion of the housing and engagingthe cable to guide the cable into a path extending down the side of thehousing to the fastening means.

22. A diesel pilehammer as defined in claim 20 wherein the lifting meansfurther comprises a cushion means for stopping the descent of thelifting mechanism after the release thereof to prevent the mechanismfrom rebounding to a position of interference with the descent of thepiston.

References Cited UNITED STATES PATENTS 2,093,634 9/1937 Cordes 173-1372,804,856 9/1957 Spurlin 173-135 2,882,690 4/1959 Frederick 173-1343,303,892 2/1967 Nishimura et al 173-135 JAMES A. LEPPINK, PrimaryExaminer. 173-137

